Timing for Dummies

[Darwinskeeper]

Purchased up a dial back timing light and hooked it up to Darwin and played with the initial timing last Saturday. I read the instructions and I think I improved matters a bit but I still have a few questions.

The instructions ask to attatch the inductive lead to the #1 spark plug wire, where is that on a Chevy 4.3 V6? Is it the forward most cylinder on the left bank?

Where on the wire is the best place to place the inductive lead? Near the spark plug? Near the distributor? (an HEI in my case) In the middle?

Do you need to disconnect the vacuum advance and plug the hose when using the timing light?

I know that these may sound like awfully dumb questions , but I'm really new at this and every turn of the screwdriver seems like a misadventure sometimes.

 

[Doober]

#1 is still the same as an SBC. Think of it as a 350 with 2 cylinders gone. I always put the pickup for the timing light close to the plug as possible, but I'm not sure it entirely matters. Also, you do need to unplug the vacuum advance & plug the hose, with it plugged in it advances the timing somewhat to help idle quality. I would say give it about 14º initial advance (vacuum advance unplugged, etc.), and go from there.

My dad has timed an engine both ways... initially he would advance it little by little, each time shutting the engine off and trying to start it back up. If it had trouble turning over, then he backed it off a little. I like the timing light method since it gives a more accurate idea of where timing is.

Now that I have a balancer with more than just 0º-12º I can actually see where my timing curve lies. I had somewhat of a fast advance in when I had the 305, which was a bad idea because where it had a snappy idle, it wanted to spark knock something fierce, and where it wouldn't spark knock, it didn't idle all too great. Wasn't too concerned because I was slowly working up to building the 350, which I put a slightly slower advance in, and it's seem to run well, but I may try upping it a hair (got a 3-weight set from Summit when I did the rebuild) to see how it does.

I'm new to tuning the spark curve myself, but here are some things I plan to look for:

• Responsive idle
• Reasonable running temperatures (too much advance driving down the expressway your temps may want to creep up)
• No spark knock
• Increased MPG

I averaged about 17-18mpg last year with one cylinder burning absurd amounts of oil (1qt./100 miles or so), so I'm hoping it will be better this year.

Sorry to hijack your thread a bit, but I fear if I don't spit out my ideas they'll just disappear with no chance of return :lol: Plus I think they might be some help here